Diversity makes a difference: Farmers managing inter- and intra-specific tree species diversity in Meru Kenya

Farmers plant trees in pursuit of their livelihood goals of income generation, risk management, household food security and optimum use of available land, labour and capital. Trees also play a crucial role in the cultural life of people. The many products, services and roles needed by people to be fulfilled by trees cannot be provided by only a few species. This research project was conceived to address the problem of Meru farmers in centralKenyarelying heavily on a single tree species, Grevillea robustaA. Cunn.(Proteaceae).This Australian species is used mainly for construction, firewood and as a boundary marker.With the disappearance of natural forest aroundMeru,Kenya, this over-reliance increasingly poses economic and environmental risks. Building on earlier research, this project started in 1998. To ensure that farmers would benefit maximally, a research approach that was participatory and constructivist was chosen. Initial research questions therefore had to be both broad and flexible. How can tree species improve farmers' livelihood goals? As a secondary question, how can the use and conservation (in the face of continued natural deforestation) of tree species in the region be improved? Given an over-reliance on Grevillea robusta , my starting point was to undertake on farm tree species trials in Meru to identify a number of suitable species for diversification purposes.Additionally ageneral nursery survey in Meru was conducted to improve the understanding of nursery practices and delivery pathways of tree species to the farms.Chapter 1 showed that the project had a flexibility to learn of the continuous input from the farmers, extension workers and scientists thereby shaping a research activity. Starting as aspeciespreference trial, the research project developed into an analysis of the opportunities and constraints of domestication of the total tree component in the landscape of Meru district.In Chapter 2 the variousresearch activities that evolved in the process (Chapter 1) of carrying out the project are discussed. Results weretriangulated, givinga detailed analysis of the Meru farmers' perception of tree species diversity and tree diversity management in general. Concerns for losses of local knowledge and biodiversity (including genetic erosion) were observed.Chapter 3 showed that many findings of the Meru case study (Chapter 2) are supported by other case studies fromCameroon,Western KenyaandUganda. This larger data set allowed for more thorough statistical analyses and provides options for diversification.Again, concerns for genetic erosion were observed.Chapter 4 addressed some of the constraints identified in Chapters 2 and 3; with low densities and a limited amount of germplasm from outside the farming community, some species may be vulnerable for inbreeding and genetic erosion in the landscape.Chapter 5 surveyed the current practices and knowledge of on-farm nurseries in Meru. Nurseries are an important part of future on-farm tree cover. This study supported the results about knowledge losses and biodiversity losses, in particular the vulnerability for genetic erosion.Chapter 6 expanded on the results of Chapter 5 regarding seed collection practices. The research was extended by additional surveys fromArushainTanzania,NairobiinKenya,KabaleinUgandaandMukonoinUganda. These showed that current seed collection procedures practiced by nursery managers provide a clear bottleneck in delivering genetic diversity to farmers.Chapter 7 provides an in-depth case study of a single species ( Vitex fischeri ), in order to quantify the anthropogenic effect on the domestication process as identified in Chapters 2 to 6.Most research activities described in this book were conducted in Meru. The inclusion of data from other locations provided a greater quantitative basis to address the specific research questions highlighted (Chapters 3, 6 & 7). Another reason to include data from other locations was because the inventory and nursery survey were of different geographic scale.This study observed a limited access to species, a risk of losing knowledge and vulnerability for genetic erosion. These factors likely cause short-term productivity and long-term stability losses in agroforest ecosystems and hamper farmers from making decisions to optimise their livelihood goals. It also erodes the biodiversity on which farmers depend. The best option to prevent this degradation of agroforest ecosystems is to assist farmers in diversifying the farm in terms of species as well as species evenness through increasing the number of trees of rare species, or through a substitution of the more common species. Farmers, extension workers and scientists active in tree domestication could focus on improving access to germplasm of a wider range of species. Addressing access to germplasm and knowledge simultaneously will allow farmers to decide for themselves, instead of research and extension only concentrating on a few 'high priority' species.Tree species preferences are largely determined by knowledge and this may lead to a bias for common species. Therefore, species preference lists must be interpreted with great caution.Using two common species, Vitex fischeri and Prunus africana(not in this thesis),as examples, no indications were found that genetic erosion has as of yet occurred in the domestication process. The on-farm stands are still suitable as seed source and farmers can continue accessing their own germplasm. The species, although both classified as locally vulnerable on the CITES list, are conserved through their use.Because of the large number of species concerned, interventions in the genetic resource management of the species diversity on farm should be facilitating and training farmers in accessing their own germplasm, preferably from other farms not within the near vicinity. For indigenous species sources within the same agro-ecological zone are preferred to ensure productivity and conserve the genetic integrity of the local populations.An efficient means to support the use and conservation of tree biodiversity is through local interactions and including the poor.